Creatinine Dextrose Bromothymol Blue
Thymine (CDBT) Agar

For differentiation of C. neoformans var. neoformans and C. neoformans var. grubii (Irokanulo et al. 1994).

Solution A

• Creatinine 1 g
• Dextrose 0.5 g
• KH2PO4 1 g
• MgSO4.7H2O 0.5 g
• Thymine 0.1 g
• Distilled water 980 mL

1. Dissolve ingredients in small beaker and adjust pH to 5.6
2. Store in refrigerator.

Solution B (Aqueous Bromothymol Blue)

• Bromothymol Blue 0.4 g
• 0.01N NaOH 64 mL
• Distilled water 36 mL

1. Dissolve the Bromothymol Blue in the NaOH
2. Add to the water.

To prepare medium (1 litre for plates):

• Solution A 980 mL Solution B 20 mL
• Bacto agar (BD 214010) 20 g
• Autoclave to 121C for 15 minutes, cool to 48C and dispense as plates.